Oxygenate to olefins reaction systems typically convert oxygenates to olefins products. In particular, methanol to olefins reaction systems utilize methanol as the primary feed for the conversion process, and these processes typically use molecular sieves as catalysts.
U.S. Pat. No. 7,071,136 discloses molecular sieves containing [AlO4] and [SiO4] tetrahedral units can be used as a catalyst to convert methanol to olefins such as ethylene and propylene. The particular catalysts are considered to be highly attrition resistant, which is a preferred characteristic for the operation of the reaction system.
U.S. Pat. No. 6,844,291 B2 discloses a molecular sieve catalyst composition that includes a metal oxide. Combining the metal oxide with the molecular sieve was considered to enhance olefin yield and catalyst lifetime in the oxygenate to olefin reaction process.
The oxygenates to olefins process is typically carried out in a fluid bed reactor and regenerator system. The catalyst particles used in the process typically range in particle size from 1 to 200 microns. An average particle size is on the order of 75 microns. Due to catalyst attrition and retention efficiency there is a tendency for catalyst particles, particularly fine catalyst particles on the order of 20 microns or smaller, to be lost from the system exiting with both the reactor and regenerator vapor effluent streams.
“Lower catalyst resistivities raise precipitator efficiencies,” Oil & Gas Journal, Aug. 10, 1998, pp. 78-79, describe the use of electrostatic precipitators to separate catalyst particles from fluid catalytic cracking units. It is desirable, however, to provide processes to reduce catalyst loss in olefin product and regenerator flue gas streams in oxygenate to olefins reaction systems.